Mac OS X Lion puts new keys on MacBook Air and changes your Mac

Mac OS X Lion has roared on to Apple Mac computers, and new computers are making changes for Lion's button-pressing paws.

New keyboards have new buttons to fire up some of Lion's new features. New standalone keyboards and the keyboards on new iMacs and MacBooks have Mission Control and Launchpad buttons, calling up a view of all your windows or all your apps.

Lion makes its first appearance on the new MacBook Air, released at the same time. The Air now has a backlit keyboard, and the keyboard also contains the new Lion-focused keys.

The new Lion-centric keys replace the Exposé and Dashboard buttons on current Macs. When you install Lion, the Exposé key now calls up Mission Control, but the Dashboard key still takes you to the Dashboard. We can't see ourselves using either of them much, as Mission Control is much easier to reach with a gesture, while a four-finger swipe to the Dashboard is probably easier for those who don't use Spaces much.

The Air also features new keys to control the backlit keyboard, returned to the range after the last version was unilluminated. The previously unused F5 and F6 keys now control the keyboard lighting.

The backlit keyboard reacts to ambient light, sensed by the webcam. To turn it on permanently, head for system preferences, go to keyboard settings and uncheck the option to automatically illuminate the keyboard in low light.

Existing Macs can be upgraded to Lion by downloading it from the Mac App Store. If you can't download Lion or want a physical back-up, it'll be available on a USB stick in August -- but it'll cost you.